Temporal linkage between breathing and swallowing is critical for airway protection because these functions share the pharynx as a common pathway. Disruption of this linkage is a significant concern in diseases with oropharyngeal dysphagia. Ataxia-Telangiectasia (A-T) is a monogenic condition that causes progressive neurodegeneration and bulbar dysfunction, including swallowing dysfunction (dysphagia). The single most common cause of death is recurrent lung infections in patients with A-T. We will use Respirodeglutometric (RDT) instrumentation to characterize the respiration during deglutition in patients with A-T. RDT instrumentation is non-invasive and has accurately defined this relationship in healthy subjects across the life-span. Moreover, we will develop A-T as a model system for quantifying the progression of dysphagia in children without repeated radiation exposure. To accomplish these goals, we propose the creation of a partnership between the A-T Clinical Center (Johns Hopkins Hospital, Baltimore MD) and researchers who have defined respiratory-swallowing relationships in healthy subjects with the RDT (University of Illinois, Urbana-Champaign). This collaboration will characterize respiratory-swallow relationships with common and previously validated procedural and data analysis protocols to (a) standardize a clinic assessment tool for the evaluation of swallowing in patients with A-T and (b) provide data necessary for submission of a full- scale research grant. We hypothesize that patients with A-T will exhibit disruptions in the temporal relationships between respiration-deglutition and between respiration-phonation. The following specific aims will be addressed: Specific Aim #1. To elucidate the impact of age and disease progression on respiratory- swallow relationships in a cross-sectional group of patients with A-T. Specific Aim #2. To elucidate the impact of age and disease progression on respiratory-phonatory relationships in a cross-sectional group of patients with A-T. Long-term goals are to use respiration and deglutition coordination as an outcome measure for therapeutic clinical trials and swallowing therapies. Characterizing these relationships in patients with A-T should facilitate earlier identification of swallowing dysfunction, help track the course of dysphagic patterns, and decrease the morbidity associated with the dysphagia. Furthermore, developing A- T as a model will form the basis for applying this non-invasive technology to other children with dysphagia. [unreadable] [unreadable] [unreadable]